1. Field of the Invention
The present invention relates generally to aircraft, and more specifically to high altitude (stratoshperic), extended flight aircraft with variants capable of medium to low altitude flight for cargo transport or other tasks. More particularly, the invention comprises an unmanned hybrid winged airship (dynastat) designed for sustained flight utilizing electrically powered engines deriving electrical energy from on board solar collection cells and/or radio frequency (RF) energy collected by on board microwave antennas receiving RF signals from RF transmitters on the ground specifically located for this purpose.
2. Description of the Prior Art
Over time, airships have been developed in a variety of configurations ranging from the earliest hot air balloons to the great airships of the 1930s. The era of great transport airships was interrupted with the crash of the Hindenburg in 1937, and the development larger versions of the faster, fixed wing transport planes. More recently, relatively small blimps have been the predominant airship in use, being used primarily for promotional purposes and as short term platforms for camera equipment for sporting events.
Long term, high altitude (stratospheric) flight, either straight line or fixed position is desirable for a variety of reasons, including communications, weather monitoring and intelligence surveillance. Orbital satellites are expensive to put into place and, once in place, maintenance or modifications are difficult or impractical to carry out. Fixed winged (aerodyne) heavier-than-air (HTA) aircraft are more economical to operate and can be easily put into place, but altitude and flight duration limitations do not make them practical for long term communications, environmental sampling and monitoring, or imaging applications. Lighter-than-air (LTA) airships (aerostat), such as blimps and dirigibles, while able to maintain more prolonged flight durations, lack the stability to effectively maintain a fixed position relative to the earth""s surface. A hybrid aerodyne/aerostat (dynastat) provides the best of both technologies, and a number of dynastat forms have been suggested in more recent years. None of these, however, has, singly or collectively, demonstrated the essential ingredients of the present invention, that is, multiple, low-drag, laminar-flow aerostats connected together with low-drag, high aspect ration airfoils (e.g., length over chord  greater than 10), in a tensegrity structure that allows aerostats containing patches of solar cells on their outer surface to rotate, thus maximizing exposure to the sun.
U.S. Pat. No. 5,581,205, issued to Stephen G. Wurst, et. al., on May 21, 1996, presents a HIGH ALTITUDE, LONG DURATION SURVEILLANCE SYSTEM comprising a pair of aerostats connected by rigid fore and aft wing assemblies. While a suspended gondola may be shifted to alter the center of gravity in a manner similar to the present invention, Wurst""s wings are of a heavy design, providing the rigidity that is provided by a light weight tetrahedral stabilizer and cables system of the present invention, linking high aspect ration airfoils to laminar-flow aerostats in a manner that allows rotation of the aerostats about their longitudinal axis.
U.S. Pat. No. 5,425,515, issued to Tokuzo Hirose on Jun. 20, 1995, presents an AIRCRAFT and U.S. Pat. No. 5,383,627, issued to Matsuro Bundo on Jan. 25, 1995, presents an OMNIDIRECTIONAL PROPELLING TYPE AIRSHIP, each having a plurality of aerostats joined by fore and aft wings. Both Hirose and Bundo utilize wings of a heavy, rigid construction to provide rigidity to the craft which is provided by the light weight tetrahedral system of the present invention, linking high aspect ration airfoils to laminar-flow aerostates in a manner that allows rotation of the aerostats about their longitudinal axis.
U.S. Pat. No. 5,240,206, issued to Sousuke Omiya on Aug. 31, 1993, presents an AIRSHIP, an aerostat having wing type control surfaces attached thereto. Omiya does not have the stability in flight of the present winged hybrid airship.
U.S. Pat. No. 3,856,238, issued to Frank S. Malvestuto, Jr., on Dec. 24, 1974, presents an AIRCRAFT TRANSPORTER comprising a plurality of aerostats joined by heavy wings segments placed at intervals along their length. Additional rigid fuselage members are spaced between the airships providing payload space. Again, all rigidity of the aircraft is provided by the wing/fuselage structure, as opposed to the light weight tetrahedral structure of the present invention, linking high aspect ratio airfoils to laminar-flow aerostats in a manner that allows rotation of the aerostats about their longitudinal axis.
U.S. Pat. No. 3,180,588, issued to J. R. Fitzpatrick on Apr. 27, 1965, presents a RIGID TYPE LIGHTER-THAN-AIR CRAFT wherein a plurality of aerostats are joined, side by side, by a rigid framework. Fitzpatrick is principally a large aerostat, presenting none of the control of a winged craft provided by the present winged hybrid.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.
The present invention presents a hybrid winged airship (dynastat) which is capable of sustained high altitude (stratospheric) flight, either straight line or over a fixed geographic position. The present invention is designed to be able to loiter at approximately 65,000 feet and remain stationary, relative to the earth""s surface, in head winds of 65-70 knots. The combination of the low drag laminar-airflow aerostat and ultra lightweight high aspect ratio aerodyne technologies provides a platform for long term, electrically powered flight and the mounting of a diversity of monitoring devices thereon. Generation of electrical energy through solar collectors and/or Radio Frequency (RF) antennas and electrical storage in on board batteries and/or fuel cells allows electrical regeneration to sustain long term flight, while variants of the dynastat capable of medium to low altitude flight may be powered by conventional power sources, such as diesel.
Accordingly, it is a principal object of the invention to provide a dynastat which is lightweight, low drag and stable in flight.
Another object of the invention is to provide a dynastat which combines the advantages of lighter-than-air (LTA)(aerostat) and heavier-than-air (HTA)(aerodyne) aircraft.
It is another object of the invention to provide a dynastat which is modular in design and may be constructed in varying sizes and configurations.
It is a further object of the invention to provide a dynastat which is structurally stable through principles of tensegrity, and at least partially maneuverable through active manipulation of the center of gravity.
Yet another object of the invention is to provide a dynastat which is capable of high altitude flight, with variants capable of medium to low altitude flight for cargo transport or other tasks.
It is a further object of the invention to provide a dynastat which is capable of long term flight.
Still another object of the invention is to provide a dynastat which has a renewable power source (conversion to electrical energy of solar and/or RF waves).
Another object of the invention is to provide a dynastat which is capable of autonomous flight and payload control through on board sensors, including global positioning via satellites (e.g. GPS).
An additional object of the invention is to provide a dynastat which is maneuverable by remote control through earth based transmissions.
It is again an object of the invention to provide a dynastat which is of lightweight construction.
Yet another object of the invention is to provide a dynastat which is capable of carrying and powering an array of devices thereon which may be monitored from a ground station.
Still another object of the invention is to provide a dynastat wherein solar collectors may be either fixed position or adapted to track the sun for maximum harvesting of solar energy, or both.
Another object of the invention is to provide a dynastat capable of receiving RF energy from an earth station to supplement or replace solar energy, as needed.
It is another object of the invention to provide a dynastat having microwave antennas which are either fixed position or adapted to track RF transmitters on the earth""s surface, or both.
It is again an object of the invention to provide a dynastat with efficient means for descent back to earth, including safe return to earth from stratospheric altitudes without heavy or costly mechanism for facilitating that process in the event of failure of the aerostat (loss of helium) at operational altitude.
Still another object of the invention is to provide a dynastat, solar or non-solar powered, which, at low altitudes, derives primary lift from the aerostats and maneuverability from the airfoils, thereby allowing uses as a lift vehicle.
It is again an object of the invention to provide a dynastat capable of tracking its location relative to the surface of the earth and making corrections in course to maintain a designated position.
It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.